The Lead

Scientists from the Univ. of Southampton have developed a new technique to generate more powerful, more energy-efficient and low-cost pulsed lasers. The technique, which was developed by researchers from the university's Optoelectronics Research Centre (ORC), has potential applications in a number of fields that use pulsed lasers including telecommunications, metrology, sensing and material processing.

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Physicists at Australian National Univ. have engineered a spiral laser beam and used it to create a whirlpool of hybrid light-matter particles called polaritons. The ability to control polariton flows in this way could aid the development of completely novel technology to link conventional electronics with new laser and fiber-based technologies.

Projecting images on curved screens poses a dilemma. The sharper the image, the darker it is, even when using lasers and scanning mirrors. A novel optical approach involving the use of an array of microprojectors now brings brightness and sharpness together for the first time on screens of any curvature. It also allows an increase in projection rates by about 10,000 times.

Lasers are so deeply integrated into modern technology that their basic operations would seem well understood. CD players, medical diagnostics and military surveillance all depend on lasers. Re-examining longstanding beliefs about the physics of these devices, Princeton Univ. engineers have now shown that carefully restricting the delivery of power to certain areas within a laser could boost its output by many orders of magnitude.

Action-packed science-fiction movies often feature colorful laser bolts. But what would a real laser missile look like during flight, if we could only make it out? How would it illuminate its surroundings? The answers lie in a film made by researchers in Poland who have captured the passage of an ultrashort laser pulse through the air.

Researchers in the Netherlands can now, for the first time, remotely control a miniature light source at timescales of 200 trillionths of a second. Physicists have developed a way of remotely controlling the nanoscale light sources at an extremely short timescale. These light sources are needed to be able to transmit quantum information.

An interdisciplinary development team that includes Lockheed Martin, the Air Force Research Laboratory and the Univ. of Notre Dame has demonstrated the airworthiness of a new beam control turret being developed for DARPA to give 360-degree coverage for high-energy laser weapons operating on military aircraft. An aircraft equipped with the laser has already conducted eight test flights in Michigan.

Princeton Univ. researchers have developed a way to use a laser to measure people's blood sugar, and, with more work to shrink the laser system to a portable size, the technique could allow diabetics to check their condition without pricking themselves to draw blood.

It’s official. Yale Univ. physicists have chilled the world’s coolest molecules. The tiny titans in question are bits of strontium monofluoride, dropped to 2.5 thousandths of a degree above absolute zero through a laser cooling and isolating process called magneto-optical trapping. They are the coldest molecules ever achieved through direct cooling, and they represent a physics milestone.

By zapping the air with a pair of powerful laser bursts, researchers at the Univ. of Arizona have created highly focused pathways that can channel electricity through the atmosphere. The new technique can potentially direct an electrical discharge up to 10 m away or more, shattering previous distance records for transmitting electricity through air. It also raises the intriguing possibility of one day channeling lightning with laser power.

With the help of ultracold quantum gas, physicists have achieved a 20-fold amplification of single-photon signals, a step that could aid all-optical data processing efforts. The breakthrough was made with the invention of a new type of optical transistor build from a cloud of rubidium atoms, held just above absolute zero, that is transparent to certain wavelengths of light.

MIT Lincoln Laboratory spinout TeraDiode is commercializing a multi-kilowatt diode laser system that’s bright enough to cut and weld through a half-inch of steel, and at greater efficiencies than today’s industrial lasers. The new system is based on a wavelength beam-combining laser diode design that won an R&D 100 Award in 2012. It combines multiple beams into a single output ray, allowing for a power boost without efficiency loss.

Lawrence Livermore National Laboratory researchers have developed a new and more efficient approach to a challenging problem in additive manufacturing—using selective laser melting, namely, the selection of appropriate process parameters that result in parts with desired properties.

Simple solid-state lasers consist of only one material. But quantum cascade lasers are made of a perfectly optimized layer system of different materials so the wavelength of the laser can be tuned. Now a method has been developed in Austria to create a laser and a detector at the same time, on one single chip, in such a way that the wavelength of the laser perfectly matches the wavelength to which the detector is sensitive.

With precarious particles called polaritons that straddle the worlds of light and matter, Univ. of Michigan researchers have demonstrated a new, practical and potentially more efficient way to make a coherent laser-like beam. They have made what's believed to be the first polariton laser that is fueled by electrical current as opposed to light, and also works at room temperature, rather than way below zero.

The potential of terahertz waves has yet to be reached because they are difficult to generate and manipulate. Current sources are large devices that require complex vacuum, lasers and cooling systems. A Northwestern Univ. team is the first to produce terahertz radiation in a simplified system. Their room-temperature, compact, continuous terahertz radiation source is six times more efficient than previous systems.

A new twist on 3-D imaging technology could one day enable your self-driving car to spot a child in the street half a block away or play “virtual tennis” on your driveway. The new system, developed by researchers at the Univ. of California, Berkeley, can remotely sense objects across distances as long as 30 feet, 10 times farther than what could be done with comparable current low-power laser systems.

Researchers at NIST have developed a laser-based instrument that generates artificial sunlight to help test solar cell properties and find ways to boost their efficiency. The novel NIST system simulates sunlight well across a broad spectrum of visible to infrared light. More flexible than conventional solar simulators, the laser instrument can be focused down to a small beam spot and shaped to match any desired spectral profile.

New research on perovskite-based solar cells pioneered in the U.K. suggests that they can double up as a laser as well as photovoltaic device. By sandwiching a thin layer of the lead halide perovskite between two mirrors, the Univ. of Cambridge team produced an optically driven laser which proves these cells “show very efficient luminescence”, with up to 70% of absorbed light re-emitted.

Commercial demand is driving high-tech research and development in micro-optoelectromechanical systems (MOEMS) for diverse applications such as space exploration, wireless systems, and healthcare. A new special section on Emerging MOEMS Technology and Applications in the current issue of the Journal of Micro/Nanolithography, MEMS, and MOEMS discusses these recent breakthrough achievements.

Imagine a computer so efficient that it can recycle its own waste heat to produce electricity. While such an idea may seem far-fetched today, significant progress has already been made to realize these devices. Researchers at the Univ. of Utah have fabricated spintronics-based thin film devices which do just that, converting even minute waste heat into useful electricity.

Inspired by the framework structure of bones and the shell structure of bees’ honeycombs, researchers in Germany have developed microstructured lightweight construction materials of extremely high stability. Although its density is below that of water, the material’s stability relative to its weight exceeds that of massive materials, such as high-performance steel or aluminum. It was created using 3-D laser writing.

Associated with unhappy visits to the dentist, “cavity” means something else in the science of optics. An arrangement of mirrors that allows beams of light to circulate in closed paths, or cavities, help us build laser and optical fibers. Now, a research team pushed the concept further by developing an optical “nanocavity” that boosts the amount of light that ultrathin semiconductors absorb.

Photonic devices are typically built using customized methods that make them difficult and expensive to manufacture. But at the Optical Fiber Communication Conference and Exposition next month, two new devices, a modulator and a tunable filter, are being presented that are not only as energy-efficient as some of the best devices around, but were built using standard CMOS process technology.

One of the main challenges for engineers trying to make practical terahertz wave devices is making the lasers powerful and compact enough to be useful. Engineers in the U.K. have reported their new quantum cascade terahertz laser exceeds 1 W output power. The new record more than doubles landmarks set by the Massachusetts Institute of Technology and subsequently by a team from Vienna last year.

Scientists at the Univ. of Strathclyde, U.K., have successfully demonstrated two notable high-power laser research developments: the first ever tunable diamond Raman laser and the first continuous-wave (CW) laser. Both lasers use synthetic diamond material made by California’s Element Six. The breakthrough is a significant achievement in solid-state laser engineering.